Microstructure and Mechanical Properties of Accumulative Roll Bonded AA6014/AA5754 Aluminium Laminates

2010 ◽  
Vol 667-669 ◽  
pp. 217-222 ◽  
Author(s):  
Tina Hausöl ◽  
Heinz Werner Höppel ◽  
Matthias Göken
Keyword(s):  
Mechanical Properties ◽  
Surface Quality ◽  
High Surface ◽  
Light And Electron Microscopy ◽  
High Strength ◽  
Band Formation ◽  
High Surface Quality ◽  
Good Surface ◽  
Ultrafine Grained ◽  
Elongation To Failure

Among the well-known methods of severe plastic deformation the accumulative roll bonding (ARB) process is most promising for producing ultrafine-grained (UFG) materials with extraordinary mechanical properties at an industrial scale. Besides, it has also been shown that the ARB process can be successfully used to produce multi-component materials with tailored properties by reinforcement or grading, respectively. In this work, laminates with alternating layers of the high strength aluminium alloy AA5754 and the AA6014 alloy, well-known for good formability and high surface quality, were produced by ARB at 230 °C. Microstructural and mechanical investigations were performed after 2, 4 and 6 ARB cycles by means of light and electron microscopy, nanoindentation experiments and tensile testing. After ARB processing an ultrafine-grained microstructure is obtained. The UFG microstructure as well as the local mechanical properties alter with the layer composition. With increasing number of ARB cycles the interfaces between the layers become more and more wavy by shear band formation. Compared to the pure accumulative roll bonded AA6014 the yield and ultimate tensile strength of the multi-component laminates are considerably higher and are only slightly reduced in comparison to the high strength AA5754. In terms of elongation to failure no reduction in ductility is found. The serrated yielding effect, clearly visible in AA5754, is shifted to higher strains or fully disappears, respectively, whereas in AA5754 the magnitude of serrations increases with increasing number of ARB cycles. Combining AA5754 and AA6014 sheets by ARB results in well bonded ultrafine-grained laminates which exhibit a combination of the beneficial properties of the single-component materials: high strength of AA5754 and good surface quality of AA6014.

Experimental Study of Pulsed Electrolyte Jet Machining for Small Hole

2010 ◽  
Vol 458 ◽  
pp. 307-312 ◽  
Author(s):  
Yi Quan Yu ◽  
Jian She Zhao ◽  
Bing Hui Li ◽  
Jia Wen Xu
Keyword(s):  
Surface Quality ◽  
High Surface ◽  
Pulse Power ◽  
Small Hole ◽  
High Surface Quality ◽  
Good Surface ◽  
Dc Power ◽  
Hole Making ◽  
Main Effects ◽  
Electrolyte Jet

For the difficulties of machining small hole on difficult-to-cut materials, a study of hole-making technology by pulsed electrolyte jet machining is carried out. Main effects of DC power and pulse power on the hole conicity, surface quality and drilling efficiency are studied in this paper. The experiment results show that: hole with high surface quality can be available and the hole conicity is effectively reduced by using pulsed electrolyte jet machining; DC is suitable for improving efficiency when the ECM voltage is less than 300V, while pulse power supply shall be adopted to achieve good surface quality and high drilling efficiency when the ECM voltage is more than 300V.

Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy

2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Coarse Grained ◽  
Type B ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Dislocation Strengthening

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.

scholarly journals Optimization of Ceramic Shells for Contact with Reactive Alloys

2008 ◽  
Vol 587-588 ◽  
pp. 157-161 ◽  
Author(s):  
Teresa P. Duarte ◽  
Rui J.L. Neto ◽  
Rui Félix ◽  
F. Jorge Lino
Keyword(s):  
Mechanical Properties ◽  
Surface Quality ◽  
Investment Casting ◽  
Chemical Reactivity ◽  
High Surface ◽  
Casting Process ◽  
Ceramic Shell ◽  
High Surface Quality ◽  
Complex Shapes ◽  
Investment Casting Process

Companies are continuously under pressure to innovate their products and processes. In Portugal, there are already several examples of enterprises that have chosen research groups, associated to universities, to straighten collaboration seeking the development of new materials and advanced technological processes, to produce components with complex shapes, high surface quality, and others, at low cost, for continuously more demanding applications. Unfortunately, these cases are still a very small number, and many efforts have to be done to enlarge the collaboration university-companies. Ti and other reactive alloys are important groups of metals that are under intense and continuous research and development. For example, the high mechanical properties, low density, osteointegration behavior, corrosion resistance to fluids and tissues of the human body, the ability to be sterilized, and the possibility to obtain complex shapes, makes Ti a very attractive material for medical applications. The investment casting process, using lost wax or lost rapid prototyping models, allows designers a great amount of freedom and capacity to quickly produce castings of high dimensional accuracy and excellent surface quality suitable for different applications. Many of the castings obtained by this process are immediately ready for use, avoiding costly machining operations and joining processes, making the process very attractive to produce precision parts in Ti and other reactive alloys. However, the high reactivity of the Ti raises several compatibility problems with the traditional materials employed on the ceramic shells for casting steels and non ferrous alloys. The fragile surface layer obtained on the interface Ti-ceramic shell, result of the Ti reaction with oxygen and nitrogen of the shell, significantly reduces the mechanical properties of the cast parts, making them useless. The aim of the present work is the study of the interface properties of the Ti-ceramic shell, in order to be able to manufacture ceramic shells of low chemical reactivity for the investment casting process of reactive alloys, namely; titanium alloys, inconel, aluminotitanates, and others. Ceramic shells manufactured with calcium and yttria stabilized zirconia and other non reactive ceramics were employed and the metallic interface characterized in terms of microscopic and microhardness properties.

Micropatterned freestanding magnetron sputtered Mg-alloy scaffolds

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
David Haffner ◽  
Christiane Zamponi ◽  
Rodrigo Lima de Miranda ◽  
Eckhard Quandt
Keyword(s):  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Surface Quality ◽  
Spatial Resolution ◽  
High Surface ◽  
Chemical Polishing ◽  
Surface Finishing ◽  
High Reproducibility ◽  
High Surface Quality ◽  
Sem Investigation

AbstractFreestanding scaffolds were fabricated of Mg5W (wt.% yttrium) alloy using magnetron sputtering technology. Appropriate method was found to produce scaffolds with high reproducibility, spatial resolution of 1 μm and good mechanical properties. Two different techniques were used for surface finishing, microblasting and chemical polishing. SEM investigation showed high surface quality after chemical polishing while microblasting influenced mechanical properties of the Mg5W alloy. Magnetron sputtering offers a high potential for the production of microstructured scaffolds.

The Experiment Research of Precision Grinding of Li-Ti Ferrite with Graphite Grinding Wheel

2010 ◽  
Vol 431-432 ◽  
pp. 322-325
Author(s):  
Bei Zhang ◽  
Hong Hua Su ◽  
Hong Jun Xu ◽  
Yu Can Fu
Keyword(s):  
Surface Quality ◽  
Material Removal ◽  
Removal Rate ◽  
High Surface ◽  
Ground Surface ◽  
Grinding Wheel ◽  
Precision Grinding ◽  
High Surface Quality ◽  
Good Surface ◽  
Good Surface Quality

Li-Ti ferrite used in aviation occasions needs good surface quality. In conventional grinding it is difficult to meet the surface demand. Accordingly, this paper proposed a new grinding process to change the situation. The process employed graphite grinding wheel which is always used in ultra-precision grinding of steel piece. The process can obtain good surface quality and ensure certain material removal rate. The ground surface appearance is nearly mirror-like. The lowest surface roughness of Ra value of the ground surface is 0.05μm in the experiment. The ground surface morphology is made up of spread glazed area and dispersed minute pits. The ductile regime dominates the material removal mechanism and no surface damage is induced in the process. In consideration of the results in the experiment it can be seen that grinding with graphite grinding wheel is a good finishing procedure in ferrite machining because of its obtained high surface quality.

Mechanical Properties and Aging Behavior of Ultrafine Grained Al-Ag Alloy Fabricated by Accumulative Roll-Bonding

2014 ◽  
Vol 794-796 ◽  
pp. 851-856
Author(s):  
Tadashiege Nagae ◽  
Nobuhiro Tsuji ◽  
Daisuke Terada
Keyword(s):  
Mechanical Properties ◽  
Grain Refinement ◽  
Accumulative Roll Bonding ◽  
Precipitation Hardening ◽  
Tensile Elongation ◽  
Solution Treatment ◽  
High Strength ◽  
Subsequent Aging ◽  
Roll Bonding ◽  
Ultrafine Grained

Accumulative roll-bonding (ARB) process is one of the severe plastic deformation processes for fabricating ultrafine grained materials that exhibit high strength. In aluminum alloys, aging heat treatment has been an important process for hardening materials. In order to achieve good mechanical properties through the combination of grain refinement hardening and precipitation hardening, an Al-4.2wt%Ag binary alloy was used in the present study. After a solution treatment at 550°C for 1.5hr, the alloy was severely deformed by the ARB process at room temperature (RT) up to 6 cycles (equivalent strain of 4.8). The specimens ARB-processed by various cycles (various strains) were subsequently aged at 100, 150, 200, 250°C, and RT. The hardness of the solution treated (ST) specimen increased by aging. On the other hand, hardness of the ARB processed specimen decreased after aging at high temperatures such as 250°C. This was probably due to coarsening of precipitates or/and matrix grains. The specimen aged at lower temperature showed higher hardness. The maximum harnesses achieved by aging for the ST specimen, the specimens ARB processed by 2 cycles, 4 cycles and 6 cycles were 55HV, 71HV, 69HV and 65HV, respectively. By tensile tests it was shown that the strength increased by the ARB process though the elongation decreased significantly. However, it was found that the tensile elongation of the ARB processed specimens was improved by aging without sacrificing the strength. The results suggest that the Al-Ag alloy having large elongation as well as high strength can be realized by the combination of the ARB process for grain refinement and the subsequent aging for precipitation hardening.

scholarly journals Mechanical Properties of Hybrid Graphene Nanoplatelet-Nanosilica Filled Unidirectional Basalt Fibre Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1468
Author(s):  
Ummu Raihanah Hashim ◽  
Aidah Jumahat ◽  
Mohammad Jawaid
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Glass Fibre ◽  
Graphene Nanosheets ◽  
High Surface ◽  
High Surface Area ◽  
High Strength ◽  
Basalt Fibre ◽  
Graphene Nanoplatelet ◽  
Dispersion State

Basalt fibre (BF) is one of the most promising reinforcing natural materials for polymer composites that could replace the usage of glass fibre due to its comparable properties. The aim of adding nanofiller in polymer composites is to enhance the mechanical properties of the composites. In theory, the incorporation of high strength and stiffness nanofiller, namely graphene nanoplatelet (GNP), could create superior composite properties. However, the main challenges of incorporating this nanofiller are its poor dispersion state and aggregation in epoxy due to its high surface area and strong Van der Waals forces in between graphene sheets. In this study, we used one of the effective methods of functionalization to improve graphene’s dispersion and also introducing nanosilica filler to enhance platelets shear mechanism. The high dispersive silica nanospheres were introduced in the tactoids morphology of stacked graphene nanosheets in order to produce high shear forces during milling and exfoliate the GNP. The hybrid nanofiller modified epoxy polymers were impregnated into BF to evaluate the mechanical properties of the basalt fibre reinforced polymeric (BFRP) system under tensile, compression, flexural, and drop-weight impact tests. In response to the synergistic effect of zero-dimensional nanosilica and two-dimensional graphene nanoplatelets enhanced the mechanical properties of BFRP, especially in Basalt fibre + 0.2 wt% GNP/15 wt% NS (BF-H0.2) with the highest increment in modulus and strength to compare with unmodified BF. These findings also revealed that the incorporation of hybrid nanofiller contributed to the improvement in the mechanical properties of the composite. BF has huge potential as an alternative to the synthetic glass fibre for the fabrication of mechanical components and structures.

scholarly journals Experimental investigation of the machining characteristics in diamond wire sawing of unidirectional CFRP

2021 ◽  
Author(s):  
Lukas Seeholzer ◽  
Stefan Süssmaier ◽  
Fabian Kneubühler ◽  
Konrad Wegener
Keyword(s):  
Surface Quality ◽  
Influencing Factors ◽  
Material Properties ◽  
High Surface ◽  
Workpiece Surface ◽  
High Surface Quality ◽  
High Productivity ◽  
Surface Temperatures ◽  
Process Forces ◽  
The Wire

AbstractEspecially for slicing hard and brittle materials, wire sawing with electroplated diamond wires is widely used since it combines a high surface quality with a minimum kerf loss. Furthermore, it allows a high productivity by machining multiple workpieces simultaneously. During the machining operation, the wire/workpiece interaction and thus the material removal conditions with the resulting workpiece quality are determined by the material properties and the process and tool parameters. However, applied to machining of carbon fibre reinforced polymers (CFRP), the process complexity potentially increases due to the anisotropic material properties, the elastic spring back potential of the material, and the distinct mechanical wear due to the highly abrasive carbon fibres. Therefore, this experimental study analyses different combinations of influencing factors with respect to process forces, workpiece surface temperatures at the wire entrance, and the surface quality in wire sawing unidirectional CFRP material. As main influencing factors, the cutting and feed speeds, the density of diamond grains on the wire, the workpiece thickness, and the fibre orientation of the CFRP material are analysed and discussed. For the tested parameter settings, it is found that while the influence of the grain density is negligible, workpiece thickness, cutting and feed speeds affect the process substantially. In addition, higher process forces and workpiece surface temperatures do not necessarily deteriorate the surface quality.

scholarly journals Investigation on the Surface Quality Obtained during Trochoidal Milling of 6082 Aluminum Alloy

Machines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 75
Author(s):  
Nikolaos E. Karkalos ◽  
Panagiotis Karmiris-Obratański ◽  
Szymon Kurpiel ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Manufacturing Industry ◽  
High Surface ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
High Surface Quality ◽  
Trochoidal Milling

Surface quality has always been an important goal in the manufacturing industry, as it is not only related to the achievement of appropriate geometrical tolerances but also plays an important role in the tribological behavior of the surface as well as its resistance to fatigue and corrosion. Usually, in order to achieve sufficiently high surface quality, process parameters, such as cutting speed and feed, are regulated or special types of cutting tools are used. In the present work, an alternative strategy for slot milling is adopted, namely, trochoidal milling, which employs a more complex trajectory for the cutting tool. Two series of experiments were initially conducted with traditional and trochoidal milling under various feed and cutting speed values in order to evaluate the capabilities of trochoidal milling. The findings showed a clear difference between the two milling strategies, and it was shown that the trochoidal milling strategy is able to provide superior surface quality when the appropriate process parameters are also chosen. Finally, the effect of the depth of cut, coolant and trochoidal stepover on surface roughness during trochoidal milling was also investigated, and it was found that lower depths of cut, the use of coolant and low values of trochoidal stepover can lead to a considerable decrease in surface roughness.

Variothermal Foam Injection Molding - Dimensional Stability with High Surface Quality

2017 ◽  
Vol 36 (3) ◽  
pp. 151-166 ◽  
Author(s):  
Christian Hopmann ◽  
Nicolai Lammert ◽  
Yuxiao Zhang
Keyword(s):  
Surface Quality ◽  
Surface Defects ◽  
Control Strategies ◽  
High Surface ◽  
Skin Layer ◽  
High Surface Quality ◽  
Major Disadvantage ◽  
Scope Of Application ◽  
Specific Material ◽  
Foam Injection Molding

Thermoplastic foam injection moulding offers various advantages for both processing and product design. Despite its many benefits, the moderate surface quality still constitutes a major disadvantage of this process. The mould temperature can be controlled dynamically to improve the surface quality. Different dynamic temperature control strategies are employed and analysed regarding their effectiveness and scope of application. Mould temperatures above the specific material transition temperatures allow the surface defects to be cured and enable the production of foamed thermoplastic parts with surface qualities comparable to those of the compact reference samples. The high mould temperatures during the injection phase alter the foam structure and the skin layer thicknesses, which impacts the mechanical properties.

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